Applied Ergonomics 41 (2010) 832–839 Contents lists available at ScienceDirect Applied Ergonomics journal homepage: www.elsevier.com/locate/apergo A comparison between Chinese and Caucasian head shapesq Roger Ball a,*, Chang Shu b, Pengcheng Xi b, Marc Rioux b, Yan Luximon a, Johan Molenbroek c a The Hong Kong Polytechnic University, School of Design, Core A, Hung Hom, Kowloon, Hong Kong b National Research Council of Canada, Canada c Delft University of Technology, The Netherlands article info abstract Article history: Univariate anthropometric data have long documented a difference in head shape proportion between Received 25 March 2009 Chinese and Caucasian populations. This difference has made it impossible to create eyewear, helmets Accepted 5 February 2010 and facemasks that fit both groups well. However, it has been unknown to what extend and precisely how the two populations differ from each other in form. In this study, we applied geometric morpho- Keywords: metrics to dense surface data to quantify and characterize the shape differences using a large data set Anthropometric from two recent 3D anthropometric surveys, one in North America and Europe, and one in China. The Scan comparison showed the significant variations between head shapes of the two groups and results 3D China demonstrated that Chinese heads were rounder than Caucasian counterparts, with a flatter back and Head forehead. The quantitative measurements and analyses of these shape differences may be applied in Shape many fields, including anthropometrics, product design, cranial surgery and cranial therapy. Design Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction However, the information of 1D dimension and sparse 3D land- marks could not satisfy the fitting requirements of products Knowledge of the form of the human head is essential infor- (Goonetilleke and Luximon, 2001; Meunier et al., 2000). In order to mation for a variety of fields, including design, medicine and capture more detailed 3D geometry of human body, researchers anthropometrics (Coblentz et al., 1991; Farkas, 1994; Kouchi and started using CT scan (Chen et al., 2002; Niu et al., 2009) and Mochimaru, 2004; Meunier et al., 2000). The differences in head stereophotogrammetry (Coblentz et al., 1991). Even though these dimensions among various populations have been studied (Lee and 3D geometries have brought new information for anthropometry Park, 2008; Yokota, 2005). It has also been suggested by both area, it has been found that the technologies could not be applied to popular anecdote and traditional univariate anthropometric a large number of subjects due to the procedure and difficulty of dimensions (Farkas, 1994) that Chinese and Western heads are data processing. Recently, 3D laser surface imaging technology has different. This cultural difference has made it impossible to create allowed digitization to record the entire surface of the subjects as eyewear, protective helmets and hygienic facemasks that fit both a 3D point cloud with high density (Ball and Molenbroek, 2008; groups well, as shown by the recent marketing trend advertising Goonetilleke and Luximon, 2001; Krauss et al., 2008; Meunier ‘‘Asian fit’’ versions of high-end fashion eyeglasses. However, it has et al., 2000; Robinette et al., 2002; Witana et al., 2009). The remained unknown to what extent and in precisely what way the method for processing the huge amount of laser scanning data has Chinese and Western heads differ from each other in 3D shape. become a new challenge for analyses. Traditionally, univariate anthropometrical measurements of Several surface modelling and shape description methods have human body using tape and caliper were commonly taken to been applied to 3D anthropometric data processing. In theoretical compare the cultural difference due to its simplicity (Farkas, 1994). applications, geometric morphometrics have been widely used to Later on, digitizer (Liu et al., 1999; Wang et al., 2005) and other study shape variations in biological forms in evolution (Collard and methods were used to collect 3D landmark coordinates which can O’Higgins, 2000), paleoanthropology (Ponce de Leon and Zollikofer, be used for statistical shape analysis (Bookstein, 1991; Badawi- 2001), and medical research (Hammond et al., 2004; Hennessy Fayad and Cabanis, 2007; Mutsvangwa and Douglas, 2007). et al., 2007). Kouchi and Tsutsumi (1996) studied morphological characteristics of cross-section of 3D foot shape model to find out q the relation between foot outline medial axis and 3D shape. A 3D Grant sponsorship: none. * Corresponding author. Tel.: þ852 2766 5444; fax: þ852 2774 5067. face form using the free form deformation method was analyzed E-mail address: [email protected] (R. Ball). for spectacle frames design (Kouchi and Mochimaru, 2004). 0003-6870/$ – see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.apergo.2010.02.002 R. Ball et al. / Applied Ergonomics 41 (2010) 832–839 833 In addition, the non-uniform rational Bsplines (NURBS) method was applied to reconstruct 3D human heads (Zhang and Molenbroek, 2004). Recently, surface parameterization method has been used on 3D human body frequently (Allen et al., 2003; Xi et al., 2007; Xi and Shu, 2009). When the data is manipulated with the surface parameterization technique, a statistical shape analysis comparison can be performed on whole surfaces with dense sample of coordinates. Consistent parameterization (Xi et al., 2007; Xi and Shu, 2009) deformed a generic mesh model and fit it onto each human head scan. This method has ensured that all the parameterized models are well corresponded in 3D positions where anthropometric landmarks locate, and the other parts on the parameterized models are corresponded accordingly. As a result, the same vertices denote the same semantic position on each parameterized head model. The 3D consistent parameterization thus creates a solid basis for latter comparisons, because it repre- sents the individual head shape in all directions and local positions consistently. This approach has been shown previously to be effective in studying the relationship between human facial dys- morphogenesis and cognitive function (Hennessy et al., 2007), 3D human shape variations within a population (Xi and Shu, 2009). Fig. 1. Location of Reference Plane for characteristic contour. Based on the theory of the method development, it will be appropriate method on statistical comparison of different photographs of front and side profiles; demographic data; and the populations. 3D digital scans. Therefore, the main objective of this study is to compare the 3D shape differences between Chinese and Western heads using 3D 2.1.2. CAESAR database anthropometrical data through various methods including The Civilian American and European Surface Anthropometry parameterization technique, contour and landmarks. The quanti- Resource (CAESAR) (Robinette et al., 2002) offered an extensive 3D tative measurements and analyses of these shape differences will digital database recording scan measurements of male and female help to answer practical questions in many fields, including adult civilian subjects aged 18–65. CAESAR was the first large-scale anthropometrics, product design, cranial surgery and cranial anthropometric study to record 3D digital scans of body shape in therapy. addition to traditional univariate measurements and demographic data. Digital scan data recorded the geometry of body shape in full 2. Methods 3D space, providing a detailed and accurate description of body shape, as well as automatic consistency in data collection. The 4000 In order to compare the head shape differences between Chinese and Western population, 3D head shape data was obtained from two recent digital anthropometric databases, one represent- ing North American and European Caucasians (CAESAR) and the other representing the Chinese (SizeChina). The parameterized models, the characteristic contour and the selected landmarks of these two data sets were processed and compared statistically. 2.1. Data acquisition 2.1.1. SizeChina database SizeChina was the first high resolution 3D digital anthropo- metric survey using laser scan technology to study the size and shape of the adult Chinese head (Ball and Molenbroek, 2008). The project was inspired by the widespread perception that headgear designed using Caucasian data was unsuitable for Asian users. Using Cyberware 3030 Color 3D scanner (www.cyberware.com), SizeChina documented head data from both men and women between the ages of 18 and 70þ. The scanner captured a cylinder space about 30 cm in height and 40–50 cm in diameter. The sampling pitch or scanning resolution of scanner used in SizeChina survey was 1 on theta, 0.7 mm on y (vertical) and minimum 0.1 mm on z (diameter). Scanning was conducted at six different mainland sites (Shenyang, Beijing, Lanzhou, Chongqing, Hangzhou, Guangzhou), chosen to represent a broad geographical range between north, south, east and west recording a total of more than 2000 subjects. No restrictions were placed on the height, weight or socio-economic status of volunteer subjects. Data collected from each subject included standard univariate measurements including weight, height and head dimensions; high resolution digital Fig. 2. An example of characteristic contour. Download English Version: https://daneshyari.com/en/article/548815 Download Persian Version: https://daneshyari.com/article/548815 Daneshyari.com.